Liquid crystal display device

ABSTRACT

A liquid crystal display device includes a liquid crystal panel, a transparent protective member, and a transparent adhesive material. The liquid crystal panel is an in-plane switching liquid crystal panel including a TFT substrate, a counter substrate sandwiching a liquid crystal layer between the counter substrate and the TFT substrate, and a transparent conductive film being provided on a surface opposite to the liquid crystal layer of the counter substrate, a side of the transparent conductive film being a side of a display surface. The transparent protective member covers a surface on the side of the display surface of the liquid crystal panel. The transparent adhesive material attaches the transparent protective member on the surface on the side of the display surface. The transparent conductive film has a film thickness ranging from 120 nm to 160 nm.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. patent application Ser. No.15/801,850 filed Nov. 2, 2017, which claims benefit of priority toJapanese Patent Application 2016-222038 filed Nov. 15, 2016, the entirecontent of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a liquid crystal display device, andparticularly to a liquid crystal display device in which a transparentprotective member is attached on a front surface of an in-planeswitching liquid crystal panel with a transparent adhesive material.

Description of the Background Art

In a liquid crystal display device including an in-plane switchingliquid crystal panel in which a voltage is applied in parallel with asubstrate surface, an electrode is provided in a substrate in which adrive element such as a thin film transistor (TFT) is formed (alsoreferred to as “the TFT substrate” or “the array substrate”), but is notprovided in a counter substrate in which a color filter, for example, isprovided (also referred to as “the color filter (CF) substrate). Thus,an external electrical field such as a static electricity entering froma side of the counter electrode or a charge-up on a surface of thecounter electrode may cause a defect in a display on the liquid crystalpanel.

Accordingly, adopted in the liquid crystal display device including aconventional general in-plane switching liquid crystal panel, as ameasure against an electrostatic discharge (ESD) described above, is astructure that an indium thin oxide (ITO) film having a film thicknessof approximately 25 nm is formed on a glass surface located on a side ofa display surface of the counter substrate (that is to say, a sideopposite to the TFT substrate) so as to suppress the external electricalfield entering from the side of the counter substrate. The above ITOfilm can be functionally referred to as “the transparent conductivefilm”, or also referred to as “the back surface ITO” because it isprovided on a back side with respect to a surface on which the colorfilter is disposed.

In the meanwhile, in a case where the back surface ITO is provided, adifference of refraction index between the back surface ITO, apolarization plate disposed on an upper surface of the back surface ITO,and the glass on the counter substrate located below the back surfaceITO causes an interface reflection and increases a reflection ratio ofthe liquid crystal panel, thereby causing a problem. Considered as amain factor of the increase in the reflection ratio in the aboveconfiguration is a reflection at an interface between the polarizationplate and the back surface ITO and a reflection at an interface betweenthe back surface ITO and the glass on the counter substrate. Thesereflection elements largely double the reflection ratio of the liquidcrystal panel compared with a liquid crystal display device which doesnot include the back surface ITO.

As a method of improving the reflection ratio, for example, JapanesePatent Application Laid-Open No. 2009-250989 describes a method ofplacing a low refraction index film on an upper layer or a lower layerof the back surface ITO for purpose of reducing the reflection at theinterface between the polarization plate and the back surface ITO or thereflection at the interface between the back surface ITO and the glassas described above, thereby causing the film thickness of the backsurface ITO to be relatively thin, that is approximately 10 nm to 20 nm.

In the meanwhile, as a method of enhancing the effect against the ESD,Japanese Patent Application Laid-Open No. 2012-155258 describes a methodapplying a resin layer into which conductive inorganic particles aremixed to form a transparent conductive film having a thickness ofapproximately 0.2 μm to 5 μm, and using the transparent conductive filmas the back surface ITO. Japanese Patent Application Laid-Open No.10-293207 describes an example of using an ITO film, which is formed tobe relatively thick, that is 145 nm or 180 nm, for example, bysputtering, as the back surface ITO.

Recently, a liquid crystal display device to be placed outside, forexample, includes a transparent protective plate (also referred to as “atransparent protective member” or “a cover glass”) made of resin orglass, for example, on a side of a front surface (that is to say, adisplay surface) of the liquid crystal panel to protect the liquidcrystal panel against an external impact, for example. If there is anair layer between the liquid crystal panel and the protective plate inthe above case, an external light entering from the side of the frontsurface of the liquid crystal panel is reflected by front and backsurface of the protective plate and the front surface of the liquidcrystal panel, thus a problem that a visibility in the display of theliquid crystal panel reduces occurs.

Accordingly, applied is a configuration of filling a transparent resinbetween the liquid crystal panel and the protective plate or aconfiguration of attaching the liquid crystal panel and the protectiveplate with a transparent adhesive material such as a light transmissiveadhesive sheet made of resin therebetween, for example. Theconfiguration similar to the above description is applied to the liquidcrystal display device including a touch panel on the front surface ofthe liquid crystal panel to prevent the air layer from being formedbetween the touch panel and the liquid crystal panel. As describedabove, the liquid crystal display device including the protective plateor the touch panel on the side of the front surface of the liquidcrystal panel (collectively referred to as “the front surface panel”hereinafter) has the configuration of placing the resin layer (theinjected resin or the light-transmissive adhesive sheet) between theliquid crystal panel and the front surface panel to suppress theformation of the air layer.

As described above, the liquid crystal display device including thefront surface panel originally has the problem of the reflection causedby the formation of the air layer between the front surface panel andthe liquid crystal panel as described previously, so that the measuredescribed above has been taken. However, the configuration of includingthe front surface panel has also been started to be applied to theliquid crystal display device including the in-plane switching liquidcrystal panel including the back surface ITO described previously, sothat the increase in the reflection ratio occurring compositely in thefront surface panel, the resin layer, and the back surface ITO alsobecomes one of the additional problems.

SUMMARY Problem to be Solved by the Invention

However, in a case of applying the method of adding the low refractionindex film on the upper layer or the lower layer of the back surfaceITO, thereby causing the back surface ITO to be relatively thin, that isapproximately 10 nm to 20 nm as described in Japanese Patent ApplicationLaid-Open No. 2009-250989, a process of forming the low refraction indexfilm and a material of the low refraction index film are necessary toadd the low refraction index film, thereby causing a cost increase as amatter of course. Furthermore, the thinned back surface ITO has a highresistance, so that the effect against the ESD, which is the intendedpurpose for forming the back surface ITO, is reduced.

Japanese Patent Application Laid-Open Nos. 2012-155258 and 10-293207 inthe above description describe the method of enhancing the effectagainst the ESD, but do not describe the method of improving thereflection ratio. Particularly, with regard to the problem of thereflection ratio in the liquid crystal display device including thefront surface panel on the side of the display surface of the in-planeswitching liquid crystal panel described above, Japanese PatentApplication Laid-Open Nos. 2012-155258 and 10-293207 have no descriptionof the configuration of including the front surface panel, thus do notdisclose the effective method of improving the reflection ratio in thestructure that the front surface panel is disposed on the side of thedisplay surface.

Provided is a liquid crystal display device capable of suppressing anexternal electrical field entering from a side of a counter substrateand suppressing a reflection of an external light entering from a sideof a display surface at the same time.

Means to Solve the Problem

A liquid crystal display device according to the present inventionincludes a liquid crystal panel, a transparent protective member, and atransparent adhesive material. The liquid crystal panel is an in-planeswitching liquid crystal panel including a TFT substrate, a countersubstrate sandwiching a liquid crystal layer between the countersubstrate and the TFT substrate, and a transparent conductive film beingprovided on a surface opposite to the liquid crystal layer of thecounter substrate, a side of the transparent conductive film being aside of a display surface. The transparent protective member covers asurface on the side of the display surface of the liquid crystal panel.The transparent adhesive material attaches the transparent protectivemember on the surface on the side of the display surface. Thetransparent conductive film has a film thickness ranging from 120 nm to160 nm.

Effects of the Invention

According to the present invention, the transparent conductive film hasthe film thickness ranging from 120 nm to 160 nm, thus the liquidcrystal display device, in which the transparent protective member isattached on the in-plane switching liquid crystal panel with thetransparent adhesive member, can suppress an external electrical fieldentering from a side of the counter substrate and suppress thereflection of an external light entering from a side of the displaysurface at the same time.

These and other objects, features, aspects and advantages of the presentinvention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a liquid crystal displaydevice according to an embodiment 1.

FIG. 2 is a cross sectional view of the liquid crystal display deviceaccording to the embodiment 1.

FIG. 3 is a drawing for describing a reflection in the liquid crystaldisplay device according to the embodiment 1.

FIG. 4 is a drawing illustrating a film thickness dependency of atransparent conductive film with respect to a reflection ratio in theliquid crystal display device.

FIG. 5 is a perspective view of a counter substrate and a transparentconductive film according to an embodiment 3.

FIG. 6 is a cross sectional view of the counter substrate and thetransparent conductive film according to the embodiment 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are described based on the drawingshereinafter.

Embodiment 1

<Configuration of Liquid Crystal Display Device>

FIG. 1 is an exploded perspective view schematically illustrating anexample of a configuration of a liquid crystal display device 100according to the embodiment 1 of the present invention. FIG. 2 is across sectional view taken along an arrow A-A illustrated in FIG. 1.

As illustrated in FIGS. 1 and 2, the liquid crystal display device 100includes a transparent protective member 1, a transparent adhesivematerial 2, a light-shielding film 3, an adhesive material 4, a liquidcrystal panel 5, a housing 11, and a backlight unit 12.

The liquid crystal panel 5 is an in-plane switching liquid crystal paneland includes, as illustrated in FIG. 2, polarization plates 6 and 10, atransparent conductive film 7, a counter substrate 8, and a TFTsubstrate 9. In the liquid crystal panel 5, two glass substrates, thatis to say, the TFT substrate 9 being a first substrate and the countersubstrate 8 being a second substrate are disposed to face each other,and these two substrates sandwich a liquid crystal layer (not shown)therebetween. The polarization plate 10 is attached on an outer surface(that is to say, a surface opposite to the liquid crystal layer) of theTFT substrate 9. The polarization plate 6 is attached on a surface ofthe transparent conductive film 7, which will be described hereinafter,opposite to the counter electrode 8.

A circuit portion of a pixel including the TFT is formed on a surface ofthe TFT substrate 9 on which the liquid crystal layer is disposed. Inthe meanwhile, a color filter and a light-shielding film (a blackmatrix: BM), for example, are formed on a surface of the countersubstrate 8 closer to a side where the liquid crystal layer is disposed.The transparent conductive film 7 for suppressing an entry of anexternal electrical field, for example, is formed on an outer surface ofthe counter substrate 8 (that is to say, between the polarization plate6 and the counter substrate 8). The transparent conductive film 7 needsto be formed in at least a region covering a display region 5 a in whicha video is displayed on the liquid crystal panel 5 (also referred to as“the display area”), but is disposed to cover the entire outer surfaceof the counter substrate 8 in the present embodiment. Although not shownin the drawings, the transparent conductive film 7 is grounded andconnected via a conductive paste or a conductive tape provided on aframe region outside the display region 5 a in the liquid crystal panel5.

In the present embodiment, the transparent conductive film 7 is asputtering film (specifically, an ITO film) formed by sputtering with apredetermined film thickness ranging from 120 nm to 160 nm. Herein, thetransparent conductive film 7 having an average thickness of 140 nm andvariation range of ±10% is formed as an example. A film depositiontemperature (a substrate temperature) at the time of sputtering isappropriately adjusted to adjust a film quality (or a resistivity) sothat a sheet resistance in the transparent conductive film 7 having thepredetermined film thickness ranges from 10Ω/□ to 25Ω/□.

The liquid crystal panel 5 is housed in a housing 11 together with thebacklight unit 12. The transparent protective member 1 is attached on adisplay surface on which the video is displayed on the liquid crystalpanel 5 (that is to say, the surface of the polarization plate 6opposite to the counter substrate 8) via the transparent adhesivematerial 2 to cover the display surface. It is also applicable to placean index matching layer (a lamination film of a low refraction indexlayer and a high refraction index layer) between the transparentadhesive material 2 and the polarization plate 6 to attach thetransparent adhesive material 2 on the polarization plate 6 via theindex matching layer. An AR treatment (an antireflection treatment) maybe appropriately performed on an outer surface of the transparentprotective member 1 (that is to say, a surface of the transparentprotective member 1 opposite to the transparent adhesive material 2).The transparent protective member 1 may be replaced with a touch panel,for example.

The transparent protective member 1 is attached on the surface of theliquid crystal panel 5 with the transparent adhesive material 2, andalso is attached on and fixed to the housing 11 with the adhesivematerial 4 disposed on a periphery of a surface of the transparentprotective member 1 closer to the liquid crystal panel 5. When the sizeof transparent adhesive material 2 is changed to be substantially thesame as that of the transparent protective member 1, the transparentprotective member 1 can be fixed to both the surface of the liquidcrystal panel 5 and the housing 11 only with the transparent adhesivematerial 2, and the adhesive material 4 may be omitted in the abovecase.

The transparent adhesive material 2 suppresses the formation of an airlayer in an area where the transparent adhesive material 2 is applied,thus can be appropriately selected from a resin layer such as aninjection resin or a light-transmissive adhesive sheet. A combination ofthe material is selected so that the transparent adhesive material 2 hassubstantially the same refraction index as the transparent protectivemember 1 or a difference of the refraction index between the transparentadhesive material 2 and the transparent protective member 1 is at leastequal to or smaller than 30% of the larger refraction index.

As illustrated in FIGS. 1 and 2, the light-shielding film 3, having ashape along the periphery of the surface of the transparent protectivemember 1 closer to the side where the liquid crystal panel 5 isdisposed, is formed on the periphery. The light-shielding film 3 isformed to have a frame shape with an opening portion 3 a, and a size ofthe opening portion 3 a is the same or slightly smaller than that of thepolarization plate 6 in a planar view, and is substantially the same asthat of the display region 5 a in the liquid crystal panel 5. Thelight-shielding film 3 prevents light emitted from the backlight unit 12from being visually recognized from the outside of the display region 5a in the liquid crystal display panel 5 or prevents light leaked fromthe periphery of the counter substrate 8 from being visually recognizedfrom the side of the display surface. The light-shielding film 3 is afilm formed by printing a black ink, for example, thus is also referredto as “a black-framed printing”, for example, in some cases.

<Operation and Effect>

Subsequently, an operation and an effect obtained in a structure of theliquid crystal display device 100 according to the present embodiment 1are described in detail hereinafter.

FIG. 3 is a drawing for describing a reflection in the liquid crystaldisplay device 100. FIG. 3 illustrates an enlarged lamination structureof the transparent protective member 1 to the counter substrate 8 in theliquid crystal display device 100. As indicated by arrows in FIG. 3, thereflection in the liquid crystal display device 100 occurs due to aninterference of a surface reflection and an interface reflection on eachof the layers of the transparent protective member 1 to the countersubstrate 8. In the example in FIG. 3, the reflection in the liquidcrystal display device 100 occurs due to the interference of thereflection on each of the surface of the transparent protective member 1(that is to say, the surface on the side of the display surface of theliquid crystal display device 100), the interface between thetransparent protective member 1 and the transparent adhesive material 2,the interface between the transparent adhesive material 2 and thepolarization plate 6, the interface between the polarization plate 6 andthe transparent conductive film 7, and the interface between thetransparent conductive film 7 and the counter substrate 8.

“The reflection in the liquid crystal display device 100” in the presentdescription indicates, as described above, the reflection occurring dueto the interference of the reflection light, which is the external lightentering from the side of the display surface of the liquid crystaldisplay device 100 and then reflected by the surface of the transparentprotective member 1, with the interface reflection of the light enteringinside the liquid crystal display device 100 from the opening portion 3a in the light-shielding film 3 and then reflected by each interfacebetween the layers described above.

In the present embodiment, the AR treatment is performed on the surfaceof the transparent protective member 1 to reduce the reflection on thesurface thereof. When the AR treatment is performed, the transparentprotective member 1 becomes the transparent protective member 1including a thin film layer having an antireflection function on thesurface thereof. Since the transparent adhesive material 2 hassubstantially the same refraction index as the transparent protectivemember 1, the reflection on the interface between the transparentprotective member 1 and the transparent adhesive material 2 is reduced.The reflection on the interface between the transparent adhesivematerial 2 and the polarization plate 6 can be reduced by sandwichingthe index matching layer therebetween. As the other reflection element,the reflection due to the interference of the surface reflection on thetransparent conductive film 7 with the reflection on the interfacebetween the transparent conductive film 7 and the counter substrate 8significantly contributes to the reflection ratio of the liquid crystaldisplay device 100.

FIG. 4 is a drawing illustrating a film thickness dependency of atransparent conductive film with respect to a reflection ratio in theliquid crystal display device. Described hereinafter using FIG. 4 is aninfluence of the film thickness of the transparent conductive film 7 onthe reflection due to the interference of the surface reflection on thetransparent conductive film 7 significantly contributing to thereflection ratio of the liquid crystal display device 100 with thereflection on the interface between the transparent conductive film 7and the counter substrate 8 (referred to as “the first reflectioncomponent” hereinafter) and the reflection including the otherreflection as well as the reflection described above in a structurehaving the transparent protective member 1 and the transparent adhesivematerial 2 (referred to as “the second reflection component”hereinafter).

Each of graphs indicated by a solid line and a dotted line in FIG. 4indicates the film thickness dependency of the transparent conductivefilm with respect to the reflection ratio occurring due to theinterference of the reflection on the surface and the interface betweeneach layer calculated using a model, in which the lamination structureof laminating the glass substrate used for the counter substrate, thetransparent conductive film, and the polarization plate in this order issimplified, at incident angles of 8 degrees and 30 degrees as a typicalexample. Data indicated by these graphs (also simply referred to as “thecalculation value” hereinafter) is used for referencing the firstreflection component (the reflection due to the interference of thesurface reflection on the transparent conductive film 7 with thereflection on the interface between the transparent conductive film 7and the counter substrate 8).

Furthermore, data plotted by black circles in FIG. 4 indicates the filmthickness dependency of the transparent conductive film with respect tothe overall reflection ratio measured using an experimental sample inwhich a transparent layer corresponding to the transparent adhesivematerial 2 (specifically, an oil layer having a refraction index of 1.5for simplifying the experiment) and a cover glass corresponding to thetransparent protective member 1 are disposed in this order on a side ofa display surface of an in-plane switching liquid crystal panel. Thisdata (also simply referred to as “the measured value” hereinafter) isused for referencing the second reflection component (the reflectionincluding the reflection as well as the first reflection component inthe structure having the transparent protective member 1 and thetransparent adhesive material 2).

Firstly, the graphs of the calculation value in FIG. 4 show that thereflection ratio can be significantly reduced when the transparentconductive film has the film thickness ranging from 0 nm to 25 nm andfrom 120 nm to 160 nm. However, the range from 0 nm to 25 nm is notpreferable regarding the effect against the ESD, and it is shown thatthe reflection ratio can be significantly reduced as long as thetransparent conductive film 7 has a predetermined film thickness rangingfrom 120 nm to 160 nm or the average thickness of 140 nm and variationrange of ±10%, as the example of the predetermined film thickness,adopted in the embodiment 1. This result corresponds to a case where theliquid crystal display device 100 particularly has a configuration, thatis, the AR treatment is performed on the surface of the transparentprotective member 1, the transparent adhesive material 2 and thetransparent protective member 1 have substantially the same refractionindex, and the index matching layer is disposed on the interface betweenthe transparent adhesive material 2 and the polarization plate 6, thusthe reflection due to the interference of the surface reflection on thetransparent conductive film 7 with the reflection on the interfacebetween the transparent conductive film 7 and the counter substrate 8mainly has the influence on the reflection ratio of the liquid crystaldisplay device 100.

In the meanwhile, the data of the measured value in FIG. 4 shows thatthe film thickness dependency of the transparent conductive film,particularly an absolute value of the reflection ratio in a thicknessregion where the reflection ratio is reduced slightly increases due tothe influence of the reflection except the first reflection component(particularly, the reflection influenced by the cover glass and thetransparent layer). This result corresponds to a case of omitting thefollowing configuration from the liquid crystal display device 100, thatis, the AR treatment is performed on the surface of the transparentprotective member 1, the transparent adhesive material 2 and thetransparent protective member 1 have substantially the same refractionindex, and the index matching layer is disposed on the interface betweenthe transparent adhesive material 2 and the polarization plate 6, forexample. However, the data of the measured value indicates the sametendency as the graph of the calculation value, thus shows that thereflection ratio can be significantly reduced when the transparentconductive film has the film thickness ranging from 0 nm to 25 nm andfrom 120 nm to 160 nm. Accordingly, it is also shown that the reflectionratio can be significantly reduced as long as the transparent conductivefilm 7 has a predetermined film thickness ranging from 120 nm to 160 nmor the average thickness of 140 nm and variation range of ±10%, as theexample of the predetermined film thickness, adopted to the liquidcrystal display device 100 according to the embodiment 1. Moreover, itis shown that since the transparent conductive film 7 has relatively thelarge thickness ranging from 120 nm to 160 nm, the effect against theESD (the effect of suppressing the entry of the external electricalfield and the charge-up) can also be effectively obtained.

With regard to the degree of the reduction in the reflection ratio, thereflection ratio can be reduced by approximately 35% to 120% comparedwith the case where the transparent conductive film has the conventionalgeneral film thickness ranging from 25 nm to 70 nm.

As described above, in the liquid crystal display device 100 includingthe transparent protective member 1 attached on the in-plane switchingliquid crystal panel 5 via the transparent adhesive member 2 accordingto the embodiment 1, the film thickness of the transparent conductivefilm 7 formed on the counter substrate 8 is set within the range from120 nm to 160 nm, thus the function of suppressing the reflection of theexternal light entering from the side of the display surface andsuppressing the external electrical field entering from the side of thecounter substrate can be achieved at the same time.

Moreover, in the liquid crystal display device 100 according to theembodiment 1, the transparent conductive film 7 is the sputtering filmformed by sputtering. The transparent conductive film 7 is thereforemade up of the transparent conductive film material having relativelythe low resistivity compared with a case where the transparentconductive film is formed of a coating-type transparent conductive filmmaterial, and further has the relatively large thickness ranging from120 nm to 160 nm. Accordingly, the sheet resistance in the transparentconductive film 7 is set within the range from 10Ω/□ to 25Ω/□. As aresult, the resistance value of the transparent conductive film 7 is setlower than the general sheet resistance of 30Ω/□, thus the effectagainst the ESD is further enhanced. The transparent conductive film 7satisfying both the range of the film thickness and the relatively lowresistance described above can be formed at the relatively low cost.

The liquid crystal display device 100 according to the embodiment 1includes the opening portion in the light-shielding film 3 havingsubstantially the same size as the display region 5 a, and moreproperly, the opening portion 3 a in the light-shielding film 3 isprovided to be slightly larger than the opening portion in the blackmatrix which is the light-shielding film provided in a surrounding partof the display region 5 a on the side of the liquid crystal panel 5 (thecounter substrate 8) determining an outline of the display region 5 a.The opening portion 3 a is set in such a manner in many cases so thatthe size or the position of a boundary of the display region 5 a doesnot fluctuate due to a misalignment caused by a relatively low accuracyin a position adjustment between the liquid crystal panel 5 and thetransparent protective material 1 on which the light-shielding film 3 isprovided. When a dummy pixel region with a constant black display isprovided in the surrounding part of the display region 5 a, a boundaryof the opening portion 3 a may be set within the dummy pixel region insome cases, however, the opening portion 3 a is set larger than thedisplay region 5 a in any case. Furthermore, a region, in which thetransparent conductive film 7 having the film thickness ranging from 120nm to 160 nm is formed, covers the display region 5 a and the entireouter surface of the counter substrate 8, that is to say, the region inthe counter substrate 8 facing the light-shielding film 3.

When the liquid crystal display device 100 is in inactive state (or ablack-display state) in the above structure, a mutual effect of the lowreflection ratio of the liquid crystal display device 100 caused by theeffect according to the basic configuration of the present inventioncauses a boundary between the light-shielding film 3 formed on thetransparent protective member 1 and the surrounding part of the displayregion 5 a in the liquid crystal panel 5 to be hardly seen. As a result,the configuration of the liquid crystal display device 100 according tothe embodiment 1 can obtain the effect of improving the visibility ofthe boundary between the light-shielding film 3 formed on thetransparent protective member 1 and the surrounding part of the displayregion 5 a in the liquid crystal panel 5. Herein, the boundary betweenthe light-shielding film 3 and the surrounding part of the displayregion 5 a specifically indicates the boundary between a black state ofthe light-shielding film 3 and a black state of the pixel in a blackdisplay state or the black matrix in the liquid crystal panel 5 (thesurrounding part of the display region 5 a). The transparent conductivefilm 7 needs to be located in at least a boundary part between thelight-shielding film 3 and the surrounding part of the display region 5a in the liquid crystal panel 5 in a planar view so as to obtain theabove effect. That is to say, since the transparent conductive film 7 isformed in the region covering the display region 5 a, it needs to extendat least from the periphery of the display region 5 a to the boundarypart of the opening portion 3 a in the light-shielding film 3 in aplanar view.

Embodiment 2

In the liquid crystal display device 100 according to the embodiment 1,the display on the liquid crystal panel 5 is colored in some cases whenthe transparent conductive film 7 is set to have a specific filmthickness, which is relatively thick, ranging from 120 nm to 160 nm. Forexample, when the transparent conductive film 7 is set to have a filmthickness which causes the display on the liquid crystal panel 5 to becolored to blue-green, specifically, a transmission rate or a reflectionratio relatively increases in a range of film thickness from 480 nm to500 nm corresponding to a wavelength range of blue-green in a singlebody of the liquid crystal panel 5.

Accordingly, for example, the color caused by the transparent conductivefilm 7 can be offset and reduced by using a member whose transmissioncharacteristics are adjusted as a constituent member other than thetransparent conductive film 7. Specifically, when the display is coloredto blue-green as the example described above, for example, it isapplicable to combine the other constituent member whose lighttransmission rate in the wavelength range from 480 nm to 500 nm isrelatively lower than a light transmission rate in the other wavelengthrange.

Although the configuration in the liquid crystal panel 5 or theconfiguration other than the liquid crystal panel 5 in the liquidcrystal display device may be selected as the member for adjusting thetransmission characteristics, it is preferable to select the transparentprotective member 1 from the perspective that a material can becomparatively easily selected. In the liquid crystal display deviceaccording to the embodiment 2, applied as the transparent protectivemember 1 is a transparent protective member having the transmissioncharacteristics to offset the transmission characteristics of thetransparent conductive film 7 (for example, the transmissioncharacteristics that the light transmission rate in the wavelength rangefrom 480 nm to 500 nm is relatively lower than the light transmissionrate in the other wavelength range so as to reduce the coloring ofblue-green, as the above description). Since the configuration in theliquid crystal display device according to the embodiment 2 other thanthe transparent protective member 1 is similar to that of the liquidcrystal display device 100 according to the embodiment 1, the detaileddescription is omitted.

In the configuration of the liquid crystal display device according tothe embodiment 2 described above, the transparent protective member 1having the transmission characteristics of offsetting the transmissioncharacteristics of the transparent conductive film 7 is used, thus thecoloring of the display can be improved in addition to the fact that theeffect similar to the embodiment 1 can be obtained.

Various Modification Examples of the Embodiment 2

As a further modification example of the embodiment 2 described above,for example, transmission characteristics of the other member may beadjusted instead of the transparent protective member 1. Somemodification examples of partially changing the configuration in theembodiment 2 are described hereinafter.

<First modification example of the embodiment 2>

In the present modification example, a member whose transmissioncharacteristics are adjusted is used as the transparent adhesivematerial 2 without adjusting the transmission characteristics of thetransparent protective member 1 in the liquid crystal display deviceaccording to the embodiment 2.

In the present modification example, the transparent adhesive material 2having the transmission characteristics of offsetting the transmissioncharacteristics of the transparent conductive film 7 is used, thus thecoloring of the display can be improved in the manner similar to theembodiment 2.

Second Modification Example of the Embodiment 2

In the present modification example, a substrate whose transmissioncharacteristics are adjusted is used as the counter substrate 8 withoutadjusting the transmission characteristics of the transparent protectivemember 1 in the liquid crystal display device according to theembodiment 2. In the present modification example, a chromaticity of thecolor filter included in the counter substrate 8 is adjusted to adjustthe transmission rate of the counter substrate 8. The chromaticity ofthe color filter may be adjusted by a ratio of the opening for eachpixel of R (red), G (green), and B (blue) (that is to say, a ratio of anarea of the opening portion of the black matrix to an area of thepixels), or it is also applicable to adjust transmission ratecharacteristics for each wavelength of each color material layer of RGB.A method of adjusting the transmission rate characteristics for eachwavelength of each color material layer includes changing a thickness ofthe color material layer or changing a contained amount of colorantmixed to develop the color.

In the present modification example, the counter substrate 8 having thetransmission characteristics of offsetting the transmissioncharacteristics of the transparent conductive film 7 is used, thus thecoloring of the display can be improved. Since the adjustment of thechromaticity of the color filter in the counter substrate 8 is one ofthe common practices performed in designing a general colorspecification, thus is preferable from the perspective that thetransmission characteristics of the counter substrate 8 can be adjustedcomparatively easily.

The embodiment 2 and each modification example thereof describe the caseof improving the coloring of the display using one member having thetransmission characteristics of offsetting the transmissioncharacteristics of the transparent conductive film 7, however, thecoloring of the display may also be improved using a plurality ofmembers having transmission characteristics of offsetting thetransmission characteristics of the transparent conductive film 7.

Embodiment 3

In the liquid crystal display device according to the embodiment 2 andthe various modification examples, the coloring of the display caused bythe transparent conductive film 7 is improved using the member havingthe transmission characteristics of offsetting the transmissioncharacteristics of the transparent conductive film 7. In the meanwhile,in the liquid crystal display device according to the embodiment 3, thecoloring of the display caused by the transparent conductive film 7 isimproved by forming a trimmed pattern (or an opening pattern) providedin a row in at least the display region 5 a having an influence on thecoloring of the display in the transparent conductive film 7.

FIG. 5 is a perspective view schematically illustrating an example ofthe configuration of the counter substrate 8 and the transparentconductive film 7 in the liquid crystal display device according to theembodiment 3. FIG. 6 is a cross sectional view taken along an arrow B-Billustrated in FIG. 5. Arrows in FIG. 6 schematically illustrate areflection of the external light by the transparent conductive film 7and the counter substrate 8. Since the configuration in the liquidcrystal display device according to the present embodiment other thanthe counter substrate 8 and the transparent conductive film 7 is similarto that of the liquid crystal display device 100 according to theembodiment 1, the detailed description is omitted.

As illustrated in FIGS. 5 and 6, the transparent conductive film 7 inthe present embodiment has a linear trimmed pattern provided in a row(that is to say, a region from which the counter substrate 8 isexposed), and in contrast, a pattern formed by the remaining transparentconductive film 7 also has a linear pattern provided in a row. Eachpattern of the transparent conductive film 7 having the linear shape maybe connected by the transparent conductive film 7 in an outer side ofthe display region 5 a and grounded and connected in the manner similarthe transparent conductive film 7 of the embodiment 1. Alternatively,each linear pattern of the transparent conductive film 7 may also beused as a wire pattern. For example, when the counter substrate 8 isconfigured to have a function as a touch panel, the linear pattern ofthe transparent conductive film 7 may also be used for a sensor wire ofthe touch panel.

In the present embodiment, as illustrated in FIG. 6, the effect similarto the embodiment 1 can be obtained in the area where the transparentconductive film 7 is included, and the reflection component of thetransparent conductive film 7 disappears in the area where thetransparent conductive film 7 is not included, thus the reflection ratioas the whole liquid crystal display device can be suppressed. Moreover,since the transparent conductive film 7 is formed by patterning, anabsolute amount of the transparent conductive film 7 is reduced, thusthe coloring the display can be improved.

The trimmed pattern provided in a row in the transparent conductive film7 in the present embodiment is not limited to the linear trimmedpattern, but a configuration of providing a rectangular opening patternin a row or a configuration of providing a slit-like opening pattern ina row is also applicable, and the effect similar to the abovedescription can be obtained as long as the display region 5 a includesthe part from which the counter substrate 8 is exposed.

Embodiment 4

In the liquid crystal display device according to the embodiment 3, thecoloring of the display caused by the transparent conductive film 7 isimproved by forming the trimmed pattern (or the opening pattern)provided in a row in at least the display region 5 a having theinfluence on the coloring of the display in the transparent conductivefilm 7. In the meanwhile, in the liquid crystal display device accordingto the embodiment 4, the coloring of the display caused by using thetransparent conductive film 7 is improved by causing the transparentconductive film 7 to have a comparatively thin film thickness within arange which is not applied in the embodiment 1.

Herein, reviewing particularly the graph of the calculation value of thefilm thickness dependency of the transparent conductive film withrespect to the reflection ratio in the liquid crystal display device inFIG. 4 which is referenced in the embodiment 1, the reflection ratio canbe significantly reduced when the transparent conductive film has thefilm thickness ranging from 0 nm to 25 nm and from 120 nm to 160 nm asdescribed previously, however, it is shown that the reflection ratio canbe reduced to some degree when the transparent conductive film has thefilm thickness ranging from 25 nm to 40 nm. In the meanwhile, alsoregarding the effect against the ESD, when the transparent conductivefilm has the film thickness ranging from 25 nm to 40 nm, the effectagainst the ESD can be expected to some degree compared with the case ofhaving the film thickness ranging from 0 nm to 25 nm. Moreover, theproblem regarding the coloring of the display which is the problem inthe embodiment 2 and the subsequent embodiments does not arise in thiscomparatively thin film thickness range. Accordingly, in the liquidcrystal display device according to the embodiment 4, the film thicknessof the transparent conductive film 7 formed on the counter substrate 8is set within the range from 25 nm to 40 nm. Moreover, the operation ofreducing the reflection ratio in the present embodiment 4 achieved fromthe operation of the transparent conductive film 7 is smaller than thatof the embodiment 1, thus the transparent protective member 1 at leastwhose surface is subject to the AR treatment is used. Since theconfiguration in the liquid crystal display device according to theembodiment 4 other than the transparent conductive film 7 and thetransparent protective member 1 is similar to that of the liquid crystaldisplay device 100 according to the embodiment 1, the detaileddescription is omitted.

As described above, in the liquid crystal display device including thetransparent protective member 1 attached on the in-plane switchingliquid crystal panel 5 via the transparent adhesive member 2 accordingto the embodiment 4, the film thickness of the transparent conductivefilm 7 formed on the counter substrate 8 is set within the range from 25nm to 40 nm, thus the function of suppressing the reflection of theexternal light entering from the side of the display surface andsuppressing the external electrical field entering from the side of thecounter substrate can be achieved on some level, and the effect enablingthe improvement of the coloring of the display can be obtained at thesame time. The transparent protective member 1 whose surface is subjectto the AR treatment, that is to say, the transparent protective member 1including the thin film layer, which has the antireflection function, onthe surface is used together, thus the function of suppressing thereflection can be complemented. Accordingly, the transparent protectivemember 1 having such a configuration is particularly effective in thepresent embodiment 4.

According to the present invention, the above embodiments can bearbitrarily combined, or each embodiment can be appropriately varied oromitted within the scope of the invention.

While the invention has been shown and described in detail, theforegoing description is in all aspects illustrative and notrestrictive. It is therefore understood that numerous modifications andvariations can be devised without departing from the scope of theinvention.

What is claimed is:
 1. A liquid crystal display device, comprising: anin-plane switching liquid crystal panel including a TFT substrate, acounter substrate sandwiching a liquid crystal layer between saidcounter substrate and said TFT substrate, and a transparent conductivefilm being provided on a surface opposite to said liquid crystal layerof said counter substrate, a side of said transparent conductive filmbeing a side of a display surface; a transparent protective membercovering a surface on said side of said display surface of said liquidcrystal panel; and a transparent adhesive material attaching saidtransparent protective member on said surface on said side of saiddisplay surface, wherein said transparent conductive film has a filmthickness ranging from 25 nm to 40 nm.
 2. The liquid crystal displaydevice according to claim 1, further comprising a light-shielding filmbeing disposed to have a frame shape with an opening portion along aperiphery of a surface of said transparent protective member closer tosaid liquid crystal panel, wherein said transparent conductive filmextends at least from a periphery of a display region in which a videois displayed on said liquid crystal panel to a boundary part of saidopening portion in said light-shielding film in a planar view.
 3. Theliquid crystal display device according to claim 1, wherein a thin filmlayer having an antireflection function is provided on a surface of saidtransparent protective member.
 4. The liquid crystal display deviceaccording to claim 1, wherein said transparent conductive film is asputtering film.